Disposable absorbent lift device

ABSTRACT

The present invention relates to a disposable absorbent pad comprising multiple layers. In particular, the absorbent pad of the present invention maintains skin dryness by absorbing moisture while preventing leakage to the skin or the bed linens, allowing air circulation at the surface of the patient&#39;s skin to prevent heat buildup, and is strong enough to allow the patient to be repositioned, even when the pad is wet. In a particular embodiment the first layer is comprised of a fluid-permeable, porous material, the second layer is disposed under the first layer and is comprised of at least one super absorbent material, and a base layer disposed under the second layer.

CROSS REFERENCE TO OTHER APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/869,432, filed Aug. 26, 2010, which is incorporated by referenceherein in its entirety.

BACKGROUND

Bed sores, also known as pressure ulcers or decubitus ulcers, areprevalent among people who are bed-ridden or otherwise immobilized. Skinulcers can be caused by pressure exerted on the skin and soft tissues(e.g., the individual's body weight resting against a hard surface suchas a bed or chair) and are exacerbated when the skin is also exposed tomoisture (e.g., due to incontinence) and/or friction, heat, and shearforces, for example caused by moving or repositioning a bed-riddenpatient.

Elderly nursing home residents are particularly vulnerable to pressureulcers since they are frequently bed-ridden and incontinent.Approximately one out of ten nursing home residents have some form ofpressure ulcers. Since pressure ulcers can be persistent and healslowly, treating pressure ulcers once formed is thus expensive, so thereis a significant need to minimize a patient's exposure to conditionswhich would cause such ulcers.

For example, it would be beneficial for bed-ridden persons who areincontinent or have other moisture management issues to lay on a pad orlayer which would not only absorb moisture but also maintain skindryness, it would also be useful to protect the bed and linens frommoisture as well in order to maintain hygiene and minimize the need forhospital staff to change bed linens. Additionally, in order to minimizeheat build up between the bedding and the patient's skin, and tomaintain skin health, it would be beneficial for the absorbent pad orlayer to allow air circulation between the pad and the skin.Furthermore, since bed-ridden patients need to be lifted andrepositioned, for example to change bed linens, for medical procedures,or to prevent the formation of pressure ulcers, it would be useful forthe absorbent pad to have sufficient strength to allow suchrepositioning.

Current products do not provide a solution to all four needs: 1)maintaining skin dryness 2) protecting the bed and linens, 3) allowingair circulation, and 4) allowing caregivers to reposition theindividual. Typically a caregiver will combine up to eight disposableunderpads to absorb moisture, as well as reusable cloth underpads orsheets to protect the bed and linens and to lift and reposition thepatient.

Combinations of multiple absorbent products are less than ideal forseveral reasons. From a strictly practical standpoint, using multipleabsorbent products is more expensive, and requires more packaging,storage, shipping costs, waste, and the like. Reusable cloth underpads,or drawsheets, are also the second most expensive item for hospitals tolaunder and process. Moreover, the combination of multiple products isnot very effective in preventing damage to the skin, while at the sametime protecting bedding. Multiple layers of absorbent pads can increasethe shear and friction experienced by individuals as the layers slideand shift against each other. Furthermore, conventional disposable padsdisintegrate when wet, and reusable cloth underpads prevent aircirculation. Furthermore, the thickness of the multiple layers caninterfere with ‘pressure management’ beds and surfaces which distributeweight to minimize or prevent excessive pressure.

There is therefore a need for an absorbent pad which maintains skindryness by absorbing moisture while preventing leakage to the skin orthe bed linens, allowing air circulation at the surface of the patient'sskin to prevent heat buildup, and which is strong enough to allow thepatient to be repositioned, even when the pad is wet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. Cross-section of an embodiment of the absorbent pad of thepresent invention.

FIG. 2. Maximum Lift Weight testing device.

DETAILED DESCRIPTION OF THE INVENTION

In various embodiments, the present invention is directed towards anabsorbent pad comprising multiple layers, e.g., three or more layers,wherein the first layer is comprised of a fluid-permeable, porousmaterial, the second layer is disposed under the first layer and iscomprised of at least one super absorbent material, and a base layerdisposed under the second layer. Additionally, the base layer has atensile strength at break, when measured by the ASTM D 882 method, inthe range of about 45 N/25 mm to 100 N/25 mm in the machine directionand about 30 to 60 N/25 mm in the cross direction.

In certain embodiments of the invention, the base later is comprised ofa third layer comprised of a hydrophobic, breathable film, disposedunder the second layer and a fourth layer, disposed under the thirdlayer, comprised of an air-permeable material.

In one embodiment of the invention, the first layer is a nonwovenmaterial. The nonwoven material of the first layer can be manufacturedusing any technique known in the art. Non-limiting examples of suitabletypes of nonwoven materials include staple nonwoven materials,melt-blown nonwoven materials, spunmelt nonwoven materials, spunbondnonwoven materials, SMS (spunbond meltblown spunbond) materials, spunlace materials, needle-felted materials, thermal-bonded nonwovenmaterials, trough-air-bonded nonwoven material, spunlaid nonwovenmaterial, air-laid nonwoven materials or the like, or any combinationsthereof.

In certain embodiments of the invention the first layer is hydrophilic.For example, the first layer can be treated in order make it fluidpermeable. Such treatments can include any treatment known in the artwhich renders a material fluid permeable. Non-limiting examples of suchtreatments include: coating the surface of the material with ahydrophilic surfactant as described in WO 93/04113 entitled “Method firhydrophilizing absorbent foam materials” and in WO 95/25495 entitled“Fluid acquisition and distribution member for absorbent core”; surfacetreatments such as corona and plasma treatment as described in describedin U.S. Pat. No. 6,118,218 entitled “Steady-state glow-discharge plasmaat atmospheric pressure”; applying a hydrophilic coating by a plasmapolymerization process as described in WO 00/16913 entitled “Durablywettable, liquid pervious webs” and WO 00/16914 entitled “Durablywettable, liquid pervious webs prepared using a remote plasmapolymerization process”; or contacting the fibers with a solution ofhydrophilic monomers and radical polymerization initiators and exposingthe fibers to UV radiation as described in U.S. Pat. No. 7,521,587entitled “Absorbent articles comprising hydrophilic nonwoven fabrics”;all of which are hereby incorporated by reference in their entirety forall purposes.

In another embodiment of the invention, the first layer is permeable tofluids such that the fluids can pass through the surface of the firstlayer toward the second layer (disposed beneath the first layer), butthe fluids cannot substantially reverse direction and move back towardthe surface of the first layer. In other words, in various embodimentsthe flow of fluids through the first layer is substantiallyunidirectional from the top surface of the first layer toward the secondlayer disposed beneath the first layer.

The first layer can comprise any suitable material known in the art. Forexample, the first layer can comprise a polymeric material. Non limitingexamples of such polymeric materials include polypropylene,polyethylene, polyethylene terephthalate, polyamide, viscose rayon,nylon, or the like or any combinations thereof. Furthermore, thepolymeric material can be a biodegradable polymeric material. One suchnon-limiting example of a polymer is the starch-based biodegradablematerial described in United States Patent Application 2009/0075346,which is hereby incorporated by reference for all purposes. In certainembodiments of the invention, the first layer has a weight per unit area(weight) in the range of about 15 gsm (grams per square meter) to about20 gsm. For example, the first layer can have a weight of about 15 gsm,about 16 gsm, about 17 gsm, about 18 gsm, about 19 gsm, or about 20 gsm,inclusive of all ranges and subranges therebetween.

In certain embodiments of the invention, the first layer is fluidpermeable. In one embodiment of the invention the first layer has aMoisture Transfer Rate, for example as measured by ASTM E96M-05 in therange of about 5 to about 200 sec/mL.

In another embodiment of the invention, the first layer is airpermeable. In certain embodiments, the first layer has an airpermeability of the range of about 10 seconds/100 mL to about 100seconds/100 mL, including about 10 seconds/100 mL, about 20 seconds/100mL, about 30 seconds/100 mL, about 40 seconds/100 mL, about 50seconds/100 mL, about 60 seconds/100 mL, about 70 seconds/100 mL, about80 seconds/100 mL, about 90 seconds/100 mL, or about 100 seconds/100 mL,inclusive of all ranges and subranges therebetween, for example asmeasured by the Gurely method using a densometer, (e.g., methodsconforming the following standards: ASTM D737 and WSP 70.1).

The second layer of the absorbent pad of the present invention isdisposed beneath the first layer, as described herein. For example, thesecond layer can be located directly beneath the first layer and indirect contact with the first layer, or adhered to the first layer bymeans of one or more intervening layers, for example an adhesive layerand/or a spacer layer.

In certain embodiments the second layer is comprised of a formedmaterial. The formed material of the second layer can be manufacturedusing any technique known in the art. Non-limiting examples of suitabletypes of formed materials include staple nonwoven materials, melt-blownnonwoven materials, spun-melt nonwoven materials, spun-bound nonwovenmaterials, thermal-bonded nonwoven materials, trough-air-bonded nonwovenmaterials, spun-laid nonwoven materials, air-laid nonwoven materials, orany combinations thereof. In a particular embodiment the second layer iscomprised of an air-laid fiber. In one embodiment the air-laid fiber isthermobonded. In a particular embodiment the air-laid material is airlaid paper.

The second layer can comprise fibers, for example natural fibers. Thenatural fibers can be any suitable natural fibers known in the art. Inone embodiment the natural fiber is cellulose. The cellulose can be fromany suitable source known in the art. Non-limiting examples of suitablesources of cellulose are wood fibers, plant fibers, field crop fibers,fluff pulp fibers, cotton, any other material, man-made or natural,designed to absorb fluid, or any combination thereof. In a particularembodiment the second layer comprises wood fibers. In anotherembodiment, the second layer comprises macerated wood pulp.

The second layer of the pad can further comprise an absorbent polymer,for example any super-absorbent polymer known in the art. Non-limitingexamples of suitable super-absorbent polymers include, for example,polymers and copolymers of acrylic acid and salts thereof (includingalkali metal salts such as sodium salts, or alkaline earth saltsthereof), polymers and copolymers of methacrylic acid and salts thereof(including alkali metal salts such as sodium salts, or alkaline earthsalts thereof), polyacrylamide polymers and copolymers, ethylene maleicanhydride copolymers, cross-linked carboxy-methyl-celluloses,polyacrylate/polyacrylamide copolymers, polyvinyl alcohol copolymers,cross-linked polyethylene oxides, starch grafted copolymers ofpolyacrylonitrile, etc. The super-absorbent polymers can be cross-linkedto suitable degree.

In a particular embodiment the super-absorbent polymer comprises sodiumpolyacrylate. In another embodiment, the second layer comprises anamount of super-absorbent polymer(s) in the range of about 15 gsm toabout 35 gsm. For example, the super-absorbent polymer(s) in the secondlayer is present in an amount of about 15 gsm, about 20 gsm, about 25gsm, about 30 gsm, or about 35 gsm, inclusive of all ranges andsubranges therebetween.

In another embodiment, the cellulose fibers of the second layer arepresent in the second layer in an amount of about 85 gsm to about 115gsm. For example, the cellulose fibers of the second layer are presentin an amount of about 85 gsm, about 90 gsm, about 95 gsm, about 100 gsm,about 103 gsm, about 105 gsm, about 110 gsm, about 115 gsm, or about 120gsm, inclusive of all ranges and subranges therebetween.

In a particular embodiment, the second layer is a thermobonded,absorbent airlaid core made from cellulose fibers and super-absorbentpolymers. In a particular embodiment of the invention, the second layeris comprised of an airlaid absorbent core as described in U.S. Pat. No.6,675,702 which is hereby incorporated herein by reference for allpurposes. In yet another embodiment, the second layer is comprised of athermobonded airlaid core made from about 100 to about 105 gsm ofcellulose fibers and 25 gsm of super absorbent polymers. In a particularembodiment, the cellulose fibers are macerated wood pulp.

The second layer absorbs substantially all of the fluids penetratingthrough from the first layer, and has a fluid-holding capacitysufficient to retain fluids without releasing the fluid through thefirst layer or through the third and fourth layers. In certainembodiments, the second layer has an absorption capacity in the range ofabout 50 cc/m² to about 20,000 cc/m², for example, about 50 cc/m², about100 cc/m², about 150 cc/m², about 200 cc/m² about 250 cc/m², about 300cc/m², about 350 cc/m², about 400 cc/m², about 450 cc/m², about 500cc/m², about 550 cc/m², about 600 cc/m², about 650 cc/m², about 700cc/m², about 750 cc/m², about 800 cc/m², about 850 cc/m², about 900cc/m², about 1,000 cc/m², about 1,100 cc/m², about 1,200 cc/m², about1,300 cc/m², about 1,400 cc/m², about 1,500 cc/m², about 1,600 cc/m²,about 1,700 cc/m², about 1,800 cc/m², about 1,900 cc/m², about 2,000cc/m², about 3,000 cc/m², about 4,000 cc/m², about 5,000 cc/m², about6,000 cc/m², about 7,000 cc/m², about 8,000 cc/m², about 9,000 cc/m²,about 10,000 cc/m², about 11,000 cc/m², about 12,000 cc/m², about 13,000cc/m², about 14,000 cc/m², about, 15,000 cc/m², about 16,000 cc/m²,about 17,000 cc/m², about, 18,000 cc/m², about 19,000 cc/m², or about20,000 cc/m² inclusive all ranges and subranges therebetween, asmeasured by the ISO11948-1 test method.

In a particular embodiment of the present invention, the second layercan be comprised of more than one fluid absorbing layer (also known as“core” layers). For example, the second layer can comprise two (or more)layers, each comprising the same or different absorbent polymer.

In order to minimize or prevent the formation of ulcers in a patientusing the absorbent pad of the present invention, the pad should remainas uniform in thickness as possible, even after absorbing fluids fromthe patient. Accordingly, the pad should not swell substantially, norshould the various layers in contact with the absorbent (second) layerseparate within the pad. Applicants have found that air laid materialscomprising a combination of a cellulosic material and a superabsorbentpolymer, as described herein do not substantially swell or separate fromthe other layers (e.g., the first and/or third layers) when wetted withfluids from the patient. By “not swell substantially” we mean that theabsorbent second layer does not increase in thickness more than about200%, for example less than about 200%, less than about 190%, less thanabout 180%, less than about 170%, less than about 160%, less than about150%, less than about 140%, less than about 130%, less than about 120%,less than about 110%, less than about 100%, less than about 90%, lessthan about 80%, less than about 70%, less than about 60%, less thanabout 50%, less than about 40%, less than about 30%, less than about20%, or less than about 10% in thickness, inclusive of all ranges andsubranges therebetween. By “not substantially separate”, we mean that atleast about 60%, for example less than about 60%, less than about 50%,less than about 40%, less than about 30%, less than about 20%, or lessthan about 10%, of the surface area of the absorbent second layerremains adhered to or in direct contact with the first and third layersof the absorbent pad (or remains adhered to or in direct contact with anadhesive and/or spacer layer disposed between the first and/or thirdlayers and the absorbent second layer).

The base layer prevents fluid absorbed in the second layer from goingthrough the bottom of the absorbent pad. The base layer should alsoprovide for air circulation within the absorbent pad to prevent heat andmoisture vapor build up.

In certain embodiments of the invention, the base layer is comprised ofa third and fourth layer, wherein the third layer is disposed under thesecond layer and the fourth layer disposed under the third layer.

The base layer (or in certain embodiments, the third layer) prevents thefluid absorbed in the second layer to penetrate through the base layerof the absorbent pad (or in some embodiments, the fourth layer). Thebase layer can comprise any natural or manmade material capable ofpreventing the flow of fluids out of the second layer and through thebottom of the absorbent pad. In certain embodiments wherein the baselayer comprises a third and fourth layer, the third layer comprises apolymeric film, for example a hydrophobic polymeric film. The polymericfilm of the third layer can be any suitable polymer known in the art,for example suitable hydrophobic polymers. Non-limiting examples of suchpolymers include polyolefins such as polyethylene, polypropylene,polylactic acid), polyhydroxybutyrate, and tapioca starch as well ascopolymers thereof. One such non-limiting example of a polymer is thestarch-based biodegradable material described in United States PatentApplication 2009/0075346, which is hereby incorporated herein byreference for all purposes.

The base layer should also provide for air circulation within theabsorbent pad to prevent heat and moisture vapor build up. Accordingly,in particular embodiments, the base layer is air permeable. Airpermeability can be provided in various ways, for example by forming abase layer comprising a third and fourth, wherein the third layercomprises a woven or nonwoven hydrophobic material which prevents themovement of bulk fluid, but allows diffusion or movement of air throughthe third layer. For example, the hydrophobic material can comprisehydrophobic polymeric fibers (e.g., polyolefin fibers) or comprisingfibers surface treated with a hydrophobic sizing or coating. In yetanother embodiment the third layer comprises a perforated polyolefin(e.g. polyethylene and/or polypropylene polymer or copolymer) sheet. Ifthe third layer comprises a perforated polyolefin sheet, theperforations should be of a size which does not permit the permeation ormovement of liquids through the perforations, but does provide airpermeability values within the ranges described herein.

Although the base layer does not permit any appreciable amount of liquidto flow through, in many instances it can be advantageous to allowmoisture vapor to permeate through the base layer. In certainembodiments of the invention, for a base layer comprising a third andfourth layer, the third layer has a moisture vapor transmission rate(MTVR) in the range of about 1,000 g/m²/day to about 10,000 g/m²/day.For example, the third layer can have an MTVR of about 1,000 g/m²/day,about 2,000 g/m²/day, about 3,000 g/m²/day, about 4,000 g/m²/day, about5,000 g/m²/day, about 6,000 g/m²/day, about 7,000 g/m²/day, about 8,000g/m²/day, about 9,000 g/m²/day, or about 10,000 g/m²/day, inclusive ofall ranges and subranges therebetween.

In yet another embodiment of the invention, the third layer has amoisture vapor transmission rate (MTVR) in the range of about 2,500g/m²/day to about 4,500 g/m²/day. For example, the third layer can havean MTVR of about 2,500 g/m²/day, about 2,600 g/m²/day, about 2,700g/m²/day, about 2,800 g/m²/day, about 2,900 g/m²/day, about 3,000g/m²/day, about 3,100 g/m²/day, about 3,200 g/m²/day, about 3,300g/m²/day, about 3,400 g/m⁷/day, about 3,500 g/m²/day, about 3,600g/m²/day, about 3,700 g/m²/day, about 3,800 g/m²/day, about 3,900g/m²/day, about 4,000 g/m²/day, about 4,100 g/m²/day, about 4,200g/m²/day, about 4,300 g/m²/day, about 4,400 g/m²/day or about 4,500g/m²/day, inclusive of all ranges and subranges therebetween.

In various embodiments of the present invention wherein the base layercomprises a third and fourth layer, the third layer has a weight in therange of about 20 gsm to about 45 gsm. For example, the third layer canhave a weight of about 20 gsm, 25 gsm, 30 gsm, 35 gsm, 40 gsm, or 45 gsminclusive of all ranges and subranges therebetween.

In one embodiment of the invention, the fourth layer is a non-wovenmaterial. The non-woven material of the fourth layer can be manufacturedusing any technique known in the art. Non-limiting examples of suitabletypes of nonwoven materials include staple nonwoven materials,melt-blown nonwoven materials, spunmelt nonwoven materials, spunbondnonwoven materials, SMS (spunbond meltblown spunbond) materials, spunlace materials, needle-felted materials, thermal-bonded nonwovenmaterials, trough-air-bonded nonwoven material, spunlaid nonwovenmaterial, air-laid nonwoven materials or the like, or any combinationsthereof.

In certain embodiments of the invention the fourth layer is hydrophobic.The fourth layer can be made of any suitable material known in the art.Non limiting examples of such materials include polypropylene,polyethylene, polyethylene terephthalate, polyamide, viscose rayon,nylon, or any combinations thereof or the like. Furthermore, thepolymeric material can be a biodegradable polymeric material. One suchnon-limiting example of a polymer is the starch-based biodegradablematerial described in United States Patent Application 2009/0075346,which is hereby incorporated herein by reference for all purposes. Incertain embodiments of the invention, the fourth layer has a weight inthe range of about 30 to about 80 gsm. For example, the fourth layer canhave a weight of about 30 gsm, about 35 gsm, about 40 gsm, about 45 gsm,about 50 gsm, about 55 gsm, about 60 gsm, about 65 gsm, about 70 gsm,about 75 gsm or about 80 gsm and all sub-ranges between.

Any embodiments of the first layer described herein can be independentlycombined with any particular embodiments of the second, third, andfourth layers described herein. For example, in a particular embodimentthe first layer is a spunbond, nonwoven sheet; the second layercomprises cellulose fibers and super absorbent polymers; the third layeris a perforated polyethylene film and the fourth layer is a nonwovensheet.

In a certain embodiments, the first layer is a spunbond, nonwoven sheetwith a weight of about 10-20 grams; the second layer comprises cellulosefibers and super absorbent polymers; the third layer is a perforatedpolyethylene film with a weight of about 30 grams and the fourth layeris a nonwoven sheet with a weight of about 40 to 60 gsm.

In other embodiments, the first layer is a hydrophilic. SMS polyethylenenonwoven sheet with a weight of about 10 to about 20 gsm; the secondlayer is a thermobonded absorbent airlaid core comprising about 103 gsmwood pulp fibers and about 25 gsm super absorbent polymers; the thirdlayer is a perforated polyethylene film with a weight of about 20 gsm,and the fourth layer is a nonwoven, BTBS film with a weight of about 50gsm. See FIG. 1.

In yet other embodiments, the absorbent pad has handles. In a particularembodiment, the handles are formed by extending the dimensions of thebase layer beyond the other two layers and forming voids in the backingmaterial. The voids can be formed for fingers or hands. In anotherembodiment, a suitable material of a suitable size can be adhered to theedge of the absorbent pad to form handles.

In various embodiments, the first, second, and base layers are adheredtogether. The layers can be adhered together using any suitabletechnique known in the art. In a particular embodiment, the layers areadhered together using an adhesive. Any suitable adhesive known in theart can be used. The adhesive used can be natural or synthetic.Non-limiting examples of such adhesives are hot melt adhesives, dryingadhesives, contact adhesives, UV curing adhesives, light curingadhesives, and pressure sensitive adhesives or the like. In oneembodiment, the top layer and the edges where the layers meet are gluedtogether using hot melt adhesive.

In various other embodiments, the pad comprises first, second, third,and fourth layers as described herein, adhered together. The layers canbe adhered together using any suitable technique known in the art. In aparticular embodiment, the layers are adhered together using anadhesive. Any suitable adhesive known in the art can be used. Theadhesive used can be natural or synthetic. Non-limiting examples of suchadhesives are hot melt adhesives, drying adhesives, contact adhesives,UV curing adhesives, light curing adhesives, and pressure sensitiveadhesives or the like. In one embodiment, the top layer and the edgeswhere the layers meet are glued together using hot melt adhesive.

Non-limiting examples of adhesives include animal glue, collagen-basedglue, albumin. glue, casein glue, Canada balsam, coccoina, pelikanol,gum Arabic, latex, methyl cellulose, library glue, mucilage, resorcinolresin, starch, urea-formaldehyde resin, acrylonitrile, cyanoacrylate,acrylic, epoxy resins, epoxy putty, ethylene-vinyl acetate, phenolformaldehyde resin, polyamide, polyester resins, polyethylene,polypropylene, polysulfides, polyurethane, polyvinyl acetate, polyvinylalcohol, polyvinyl chloride, polyvinyl chloride emulsion,polyvinylpyrrolidone, rubber cement, silicones, styrene acryliccopolymer, ethylene-acrylate copolymers, polyolefins, atacticpolypropylene, polybutene-1, oxidized polyethylene, styrene blockcopolymers, polycarbonates, fluoropolymers, silicone rubbers, or thelike and various other co-polymers. The adhesive may further compriseone or more additives. Any suitable additive known in the art can beused. Non-limiting examples of additives include, tackifying resins,waxes, plasticizers, antioxidants, stabilizers. UV stabilizers,pigments, dyes, biocides, flame retardants, antistatic agents, andfillers or the like. In particular embodiments, the adhesive comprises ahot-melt adhesive.

The adhesive layer(s) can be continuous, contacting substantially theentire surface area of any two layers adhered together (e.g. at leastabout 75%, at least about 80%, at least about 85%, at least about 90%,at least about 90%, or essentially about 100% of the surface area of thetwo layers adhered together, inclusive of all ranges and subrangestherebetween). That is, the adhesive forms an intermediate layer betweenany two layers adhered together, contacting substantially the entiresurfaces between the two layers. Alternatively, the adhesive can beapplied in a pattern (e.g., grid) or random fashion whereby the adhesivedoes not substantially contact the entire surface area of the twolayers, but rather forms a discontinuous intermediate layer between thetwo adhered surfaces. Each of the first, second, and base layers (orfirst, second, third, and fourth layers when present) of the absorbentpad of the present invention can be adhered together with continuousadhesive layers, or with discontinuous adhesive layers, or some of theadhesive layers can be continuous adhesive layers, and other adhesivelayers can be discontinuous layers. Each of the adhesive layers cancomprise the same adhesive material (as described herein), or one ormore of the adhesive layers can comprise a different adhesive material(as described herein).

The present invention can be assembled from the component layers by anysuitable method known in the art. In one embodiment of the invention,rolls of each layer are combined such that the first layer is disposedover the second, which is disposed over the base (or in someembodiments, third, which is disposed over the fourth), and the combinedlayers are then cut to the appropriate size and the edges adheredtogether. In another embodiment of the invention, sheets of a suitablesize are cut from rolls of each individual layer, then combined in theappropriate order and the edges are adhered together. In yet anotherembodiment of the invention, the dimension of the base layer exceedsthat of the second layer in either width, length or both by 1 inch to 5inches. The second layer can be disposed over the base layer such thatthe base layer extends about 0.5 to about 2.5 inches beyond the secondlayer on either opposing sides or all sides, and the material of thebase layer which extends beyond the second layer can be folded over andadhered to the second layer by any known means in the art. A first layerof the same dimensions as the second layer can be disposed over andadhered to the second layer.

In a further embodiment of the invention, the dimensions of the fourthlayer and the third layer exceeds that of the second layer in eitherwidth, length or both by 1 inch to 5 inches. The third layer is disposedover the fourth layer, and the second layer can be disposed over thethird such that the third and fourth layers extend about 0.5 to about2.5 inches beyond the second layer on either opposing sides or allsides. The material of the third and fourth which extends beyond thesecond layer can be folded over and adhered to the second layer by anyknown means in the art. A first layer of the same dimensions as thesecond layer can be disposed over and adhered to the second layer.

The pads of the present invention can be of any suitable size. In oneembodiment of the invention, the pads are about 36″ by about 31″. In oneembodiment of the invention, the pads are about 36″ by about 30″. In yetanother embodiment of the invention, the pads are about 36″ by about24″. In certain embodiment, the pads are about 36″ by about 23″. Inanother embodiment the pads are about 30″ by 30″. In yet anotherembodiment, the pads are about 24″ by about 18″. In a furtherembodiment, the pads are about 24″ to about 17″.

In a certain embodiment, the absorbent pad of the present invention hasa Total Absorption Capacity, as measured by ISO Standard 11.948-1, fromabout 4,000 g/m² to about 4,500 gm², for example about 4,000 g/m², about4,100 g/m², about 4,200 g/m², about 4,300 g/m², about 4,400 g/m² orabout 4,500 g/m².

The rate of acquisition and rewet properties of the pad of the presentinvention can be determined by any suitable method, for example theMedi-Cal method. The Medi-Cal acquisition rate and rewet test protocolscomprise laying the pad of the present invention (as described herein)on a flat surface, then rapidly adding 100 or 200 mL of a 0.09% salinesolution onto the center of the pad (the target area). The time requiredfor the saline solution to pass through the top sheet of the pad is therate of acquisition. Approximately 12 minutes after adding the salinesolution to the pad, a preweighed (˜10 g) stack of dry filter paper isplaced on the center of the target area, and weighted with a 1.0 psiweight. After 1 minute, the filter paper stack is removed and weighed.The weight of moisture absorbed by the filter paper stack is the rewetvalue.

Suitable rewet values determined by the Medi-Cal method fall within, therange of about 1 g to about 3 g, e.g., about 1 g, about 1.1 g, about 1.2g, about 1.3 g, about 1.4 g, about 1.5 g, about 1.6 g, about 1.7 g,about 1.8 g, about 1.9 g, about 2.0 g, about 2.1 g, about 2.2 g, about2.3 g, about 2.4 g, about 2.5 g, about 2.6 g, about 2.7 g, about 2.8 g,about 2.9 g, or about 3.0 g.

Suitable rate of acquisition values determined by the Medi-Cal methodfall within the range of about 110 sec to about 180 sec, e.g., about 110sec, about 115 sec, about 120 sec, about 125 sec, about 130 sec, about135 sec, about 140 sec, about 145 sec, about 150 sec, about 155 sec,about 160 sec, about 165 sec, about 170 sec, about 175 sec or about 180sec.

The “Max Lift Weight” is the maximum weight the pad can support whilebeing lifted at two or more points without tearing. The Max Lift Weightcan be tested by attaching clamps to at least two edges or corners ofthe pad and placing weights on the pad. The clamps can then be attachedto a lifting device, (FIG. 2). In certain embodiments of the invention,the absorbent pad has a Max Lift Weight in the range of up to about 415lbs to up to about 100 lbs. For Example, the absorbent pad of thepresent invention can have a Max Lift Weight of up to about 415 lbs, upto about 370 lbs, up to about 325 lbs, up to about 280 lbs, up to about235 lbs, up to about 190 lbs, up to about 145 lbs, or up to about 100lbs.

In a particular embodiment of the invention, the absorbent pad, afterexposure to about 1 mL to about 500 mL of ASTM synthetic urine or a 1%saline solution has a Max Lift Weight in the range of up to about 415lbs to up to about 100 lbs. For example, the absorbent pad of thepresent invention can have a Max Lift Weight after exposure to about 1mL to about 1000 mL of ASTM synthetic urine or a 1% saline solution ofup to about 325 lbs, of up to about 415 lbs, up to about 370 lbs, up toabout 325 lbs, up to about 280 lbs, up to about 235 lbs, up to about 190lbs, up to about 145 lbs, or up to about 100 lbs.

In some embodiments of the invention, the absorbent pad has tensilestrength at break, when measured by the ASTM D 882 method, in the rangeof about 50 N/25 mm to about 90 N/25 mm in the machine direction. Forexample, the pad can have a tensile strength at break in the machinedirection of about 50 N/25 mm, about 60 N/25 mm, about 70 N/25 mm, about80 N/25 mm, or about 90 N/25 mm, inclusive of all ranges and subrangestherebetween.

In other embodiments of the invention, the absorbent pad has tensilestrength at break, when measured by the ASTM D 882 method, in the rangeof about 30 N/25 mm to about 60 N/25 mm in the cross direction. Forexample, the pad can have a tensile strength at break in the crossdirection of about 30 N/25 mm, about 35 N/25 mm, about 40 N/25 mm, about45 N/25 mm, about 50 N/25 mm, about 55 N/25 mm, or about 60 N/25 mm,inclusive of all ranges and subranges therebetween.

In another embodiment of the invention, the elongation at break of theabsorbent pad, when tested by the ASTM D 882 method, is in the range ofabout 35% to about 115% in the machine direction. For example, the padcan have an elongation at break in the machine direction of about 35%,about 55%, about 45%, about 65%, about 75%, about 85%, about 95%, about105% or about 115%, inclusive of all ranges and subranges therebetween.

In a particular embodiment of the invention, the elongation at break ofthe absorbent, when tested by the ASTM D 882 method, is in the range ofabout 45% to about 105% in the cross direction. For example, the pad canhave an elongation at break in the cross direction of about 45%, about55%, about 65%, about 75%, about 85%, about 95%, or about 105%,inclusive of all ranges and subranges therebetween.

In particular embodiments of the invention, the absorbent pad has atensile strength at 25% elongation, when measured by the ASTM D 882method, in the range of about 35 N/25 mm to about 55 N/25 mm in themachine direction. For example, the absorbent pad can have a tensilestrength at 25% elongation in the machine direction of about 35 N/25 mm,about 40 N/25 mm, about 45 N/25 mm, about 50 N/25 mm, or about 55 N/25mm, inclusive of all ranges and subranges therebetween.

In a particular embodiment of the invention, the absorbent pad hastensile strength at 25% elongation, when measured by the ASTM D 882method, in the range of about 20 N/25 mm to about 40 N/25 mm in thecross direction. For example, the absorbent pad can have a tensilestrength at break in the cross direction of about 20 N/25 mm, about 25N/25 mm, about 30 N/25 mm, about 35 N125 mm, or about 40 N/25 mm,inclusive of all ranges and subranges therebetween.

In a particular embodiment of the invention, a single absorbent pad ofthe present invention is placed under an incontinent individual, and thesingle absorbent pad absorbs fluids, protects skin dryness and/orprotects the bedding from fluids. Protecting skin dryness means theindividual's skin which is in contact with the pad remains reasonablydry after the pad has been exposed to urine or other fluids. Protectingthe bedding means that less than 10% of the urine or other fluid whichis expelled onto the pad makes contact with the bedding underneath thepad. In yet another embodiment of the invention, at least one caregivercan lift or reposition the patient by lifting the single absorbent padof the present invention, disposed beneath the patient, at two or moreedges or corners.

EXAMPLES Example 1

A. Absorbent Pad

The first layer is a spunbond, nonwoven with a weight of 16.96 gsm(PGI). The second layer is a thermobonded absorbent airlaid core madefrom 103 gsm macerated wood pulp and 25 gsm of super absorbent polymer(Super Core® McAirlaids). The third layer is art air permeable PE filmwith a weight of 35 gsm and a MVTR of 3,600 g/m²/day (PCI). The fourthlayer is a 50 gsm spunbond nonwoven back sheet (PGI). The top layer andthe edges where the layers meet are glued together using hot meltadhesive.

B. Strength Testing

The strength of the pad from Example 1A was tested with ASTM E 252 tomeasure the basis weight and ASTM 882 to measure tensile strength andelongation at break. The results are shown in Table 1:

Property Weight/Strength Basis Weight 71.5 ± 6 g/m² Tensile Strength atbreak in the Machine 70 ± 16 N/25 mm Direction Tensile Strength at breakin the Cross 45 ± 10 N/25 mm Direction Elongation at Break in theMachine 75 ± 40% Direction Elongation at Break in the Cross 75 ± 30%Direction Tensile Strength at 25% Elongation in  47 ± 8 N/25 mm theMachine Direction Tensile Strength 25% Elongation in the  28 ± 8 N/25 mmCross Direction

C. Max Lift Weight Testing

The Max Lift Weight was tested by placing the pad flat on the groundwith the first layer up, loading weights on top of the pad and centeringthe weights. The corners of the pad were clamped into the lifting deviceas shown in FIG. 2. The absorbent pad and weights were lifted 2-3 inchesabove the ground for two minutes, while observing any tearing or otherfailures to the structural integrity of the pad. The testing wasrepeated until failure. The absorbent pad of Example 1A was held for twominutes with 415 lbs with no observed tearing or ripping.

The wet Max Lift Weight was tested in a similar manner after applying500 cc of liquid to the absorbent pad. The absorbent pad of Example 1Awas held for two minutes with 425 lbs with no observed tearing orripping.

We claim:
 1. An absorbent pad comprising: a) a first layer which isfluid permeable and air permeable; b) a second layer disposed under thefirst layer, comprising at least one super absorbent material; c) a baselayer disposed under the second layer, comprising breathable filmdisposed over an air-permeable material, wherein the absorbent pad, hasa tensile strength at 25% elongation, when measured by the ASTM D 882method, in the range of about 35 N/25 mm to about 55 N/25 mm in themachine direction and about 20 N/25 mm to about 40 N/25 mm in the crossdirection.
 2. The absorbent pad of claim 1, wherein the first layercomprises a nonwoven material.
 3. The absorbent pad of claim 2, whereinthe nonwoven material is selected from the group consisting of ahydrophilic nonwoven material, a staple nonwoven material, a melt blownnonwoven material, a spunmelt nonwoven material, a spunbond nonwovenmaterial, SMS (spunbond meltblown spunbond) materials, spun lacematerials, needle-felted materials, a thermal bonded nonwoven, a troughair bonded nonwoven material, a spunlaid nonwoven material, or anycombination thereof.
 4. The absorbent pad of claim 2, wherein thenonwoven material comprises polypropylene, polyethylene, polyethyleneterephthalate, polyamide, viscose rayon, nylon, at least onebiodegradable polymeric material or a combination thereof.
 5. Theabsorbent pad of claim 1, wherein the first layer has a weight of about10 gsm to about 20 gsm.
 6. The absorbent pad of claim 1, wherein thefirst layer has a Moisture Transfer Rate of between about 5 sec/mL toabout 200 sec/mL.
 7. The absorbent pad of claim 1, wherein the firstlayer has an air permeability in the range of about 10 seconds/100 mL toabout 100 seconds/100 mL.
 8. The absorbent pad of claim 1, wherein thesecond layer comprises formed or unformed material.
 9. The absorbent padof claim 1, wherein the second layer comprises natural or syntheticmaterial.
 10. The absorbent pad of claim 8, wherein the second layercomprises a formed material, and the formed material is an air-laidmaterial.
 11. The absorbent pad of claim 10, wherein the air-laidmaterial comprises cellulose.
 12. The absorbent pad of claim 11, whereinthe cellulose is selected from the group consisting of wood fibers,plant fibers, field crop fibers, and fluff pulp.
 13. The absorbent padof claim 1, wherein the superabsorbent of the second layer comprises apolymer or copolymer of sodium polyacrylate.
 14. The absorbent pad ofclaim 13, wherein the second layer further comprises about 90 gsm toabout 110 gsm of macerated wood pulp.
 15. The absorbent pad of claim 1,wherein the second layer has moisture absorption capacity in the rangeof about 50 cc/m² to about 20,000 cc/m² as measured by the ISO11948-1test method.
 16. The absorbent pad of claim 1, wherein the superabsorbent material does not substantially swell or separate from thefirst and/or base layers when wet.
 17. The absorbent pad of claim 1,wherein the base layer comprises: c) a third layer disposed under thesecond layer, comprising a breathable film; and d) a fourth layerdisposed under the third layer, comprising an air-permeable material.18. The absorbent pad of claim 17, wherein the third layer comprises apolyethylene film.
 19. The absorbent pad of claim 17, wherein thepolyethylene film is perforated.
 20. The absorbent pad of claim 17,wherein the third layer has a weight in the range of about 20 gsm toabout 45 gsm.
 21. The absorbent pad of claim 17, wherein the breathablefilm of the base layer is hydrophobic.
 22. The absorbent pad of claim17, wherein the third layer has a moisture vapor transmission rate inthe range of about 1,000 g/m²/day to about 10,000 g/m²/day.
 23. Theabsorbent pad of claim 17, wherein the fourth layer comprises a nonwovenmaterial.
 24. The absorbent pad of claim 23, wherein the nonwovenmaterial is selected from the group consisting of a hydrophobic nonwovenmaterial, a staple nonwoven material, a melt blown nonwoven material, aspunmelt nonwoven material, a spunbond, nonwoven material, SMS (spunbondmeltblown spunbond) materials, spun lace materials, needle-feltedmaterials, a thermal bonded nonwoven, a trough air bonded nonwovenmaterial, a spunlaid nonwoven material, or a combination thereof. 25.The absorbent pad of claim 23, wherein the nonwoven material comprises apolymer selected from the group consisting of polypropylene,polyethylene, polyethylene terephthalate, polyamide, viscose rayon,nylon, at least one biodegradable polymeric material and combinationsthereof.
 26. The absorbent pad of claim 17, wherein the fourth layer hasa weight in the range of about 30 to about 80 gsm.
 27. The absorbent padof claim 17, wherein a) the first layer is a spunbond, nonwoven sheet,b) the second layer comprises a thermobonded absorbent airlaid corecomprising cellulose fibers and super absorbent polymers c) the thirdlayer is a perforated polyethylene film and d) the fourth layer is anonwoven sheet with a weight of about 15 gsm to about 90 gsm.
 28. Theabsorbent pad of claim 1, wherein the pad has a maximum lift weight ofup to about 400 lbs.
 29. The absorbent pad of claim 1, wherein the padhas a maximum lift weight of up to about 325 lbs.
 30. The absorbent padof claim 1, wherein the breathable film of the base layer ishydrophobic.
 31. The absorbent pad of claim 1, wherein the tensilestrength at break, when measured by the ASTM D 882 method, is about70±16 N/25 mm in the machine direction and about 45±10 N/25 mm in thecross direction.
 32. The absorbent pad of claim 1, wherein theelongation at break, when tested by the ASTM D 882 method, is about75±40% in the machine direction and about 75±30% in the cross direction.33. The absorbent pad of claim 1, wherein the tensile strength at 25%elongation, when measured by the ASTM D 882 method, is about 47±8 N/25mm in the machine direction and about 28±8 N/25 mm in the crossdirection.
 34. The absorbent pad of claim 1, wherein the tensilestrength at 25% elongation, when measured by the ASTM D 882 method, isin the range of about 40 N/25 mm to about 50 N/25 mm in the machinedirection and about 25 N/25 mm to about 35 N/25 mm in the crossdirection.
 35. The absorbent pad of claim 1, wherein the tensilestrength of the base layer at break, when measured by the ASTM D 882method, is in the range of about 45 to about 100 N/25 mm in the machinedirection and about 30 to about 60 N/25 mm in the cross direction.